1. Field of the Invention
The present invention relates to an aqueous inkjet pigment dispersion, a method for producing the same, and an aqueous inkjet ink.
2. Description of the Related Art
In recent years, by virtue of the progress in inkjet recording technologies, inkjet recording methods have come to be used to obtain high-precision images in photography and offset printing, and there is a demand for high-quality recording based on inkjet recording.
In regard to the demand described above, JP2004-43776A discloses a method for producing an ink that has excellent dispersion stability and produces printed matter having excellent color developability or transparency, the method comprising a step for obtaining a solution including a water-insoluble coloring material and a dispersant dissolved in an aprotic organic solvent in the presence of an alkali; a step for mixing this solution with water, and obtaining a dispersion in which particles containing the water-insoluble color material and the dispersant are dispersed; a step for aggregating the dispersion through addition of an acid, and thus separating out aggregates; and a step for redispersing the particles of the aggregates through an alkali treatment.
JP2011-231315A discloses an ink composition which uses a polymerizable compound and a pigment dispersoid, the ink composition being an ink composition which exhibits excellent ejection reliability over a long time period and is capable of forming images that are free of defects such as white streaks. The disclosed ink composition includes a pigment coated with a dispersive polymer that is obtainable by crosslinking a water-soluble dispersant with a crosslinking agent, and also includes a water-soluble polymerizable compound, a polymerization initiator, and water.
JP2010-7020A discloses a pigment dispersion in which a pigment is finely dispersed, and even in a case in which the pigment dispersoid has been stored for a long time period, the pigment exhibits excellent dispersion stability, the pigment dispersoid including a pigment; a polymer containing a repeating unit having a particular structure having a resin acid derivative and having a weight-average molecular weight in the range of 10,000 to 1,000,000; and a polymerizable compound.